coaltech upper olifants river catchment wetland inventory ...

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5.11.4 Pans Pans are typically circular to oval shallow depressions without an outflow and seldom more than three meters deep, although deeper systems have been defined as pans. It is also often difficult to distinguish between pans and lakes. Since no lakes have been classified, all of the wetlands complying with the requirements have been included as either non-perennial or perennial pans (Allan et al 1995). Since most of the pans had already been identified in the three existing wetland layers a large portion of the pans have already been delineated. Pans in general are fairly small with the perennial pans being larger than the non-perennial pans, but the non-perennial pans are more numerous. Only 1.5% of the total wetland area is perennial pans, while 2.5% of the wetland area is non-perennial pans. 5.11.5 Artificial Wetlands Artificial wetlands are any type of wetland constructed by man and mostly include dams and weirs. In this case the dams are included in a separate layer and the artificial wetlands only include those wetlands that are obviously anthropogenic, excluding dams. Some of the wetlands may however be a result of a dam or weir, upstream or downstream of the wetland. Less than 0.2 % of the wetlands in the catchment are indicated as artificial wetlands, although it is suspected that a much larger percentage of the wetlands may be artificial. 5.12 Dams Although dams are not included in the DWAF definition of a wetland, a layer of the dams has been included, since dams can perform some wetland functions. Dams are, however, a threat to most wetlands and riverine systems by changing the hydrological patterns, sediment load and temperature of the wetlands and rivers although they provide habitat to various wetland species including frogs, birds and invertebrates. Although the dams in the UORC are numerous (3 701 in total) they have a total extent of approximately 120 km 2 , and therefore only cover about 5.6 % of the total catchment area. Wetland Database for UORC - 88 -
6. DATABASE CONSTRAINTS The greatest problem was the lack of georeferenced aerial photographs for the area. Google Earth was investigated to determine if it would provide value to the project, but the quality of the images was too poor for the purpose of this project. The 1:50 000 aerial photographs, as obtained from the Chief Directorate: Surveys and Mapping at the Department of Land Affairs, Mowbray, Cape Town, was the only complete set of aerial photographs available for the site. The georeferencing of these aerial photographs was based on the 1:50 000 topographical map and accuracy is therefore dependant on the accuracy of the topographical layers. In addition, all aerial photographs are skewed towards the edges due to the concave structure of the camera lens. We attempted to correct this feature during the georeferencing process, but the effect could not be removed completely. The wetlands located to the edges of the aerial photographs may therefore be slightly removed from their exact position. Where areas under cultivation were obviously located on a seepage area the wetland was indicated and the status of the wetland was given as E or F (destroyed). Some additional seepage areas covered by cultivation may occur, but have not been identified. This is because wetlands under cultivation are not easily distinguished. Patchiness in a cultivated area can be caused by a number of influences, including differences in soil and patchy distribution of fertiliser, in addition to the presence of seepage wetlands. Other highly disturbed wetlands may also not be identifiable on the aerial photographs as wetlands and these wetlands will be absent from the wetland layer. In addition, small wetlands are not visible on the 1:50 000 aerial photographs and are therefore not included. Tonal variations between the aerial photographs complicated the mapping of the wetlands on the aerial photographs. The changes from one strip of aerial photographs to another may be due to the time of day the photographs were taken and the light quality. Even without cloud cover the light quality may differ from day to day. 7. COMPARISON TO THE NATIONAL LANDCOVER WETLAND LAYER The final Landcover wetland layer, completed in June 2006, was compared to the completed UORC wetland database. The Landcover wetland layer compared very well to the UORC wetland database, since all of the Landcover wetlands were already identified in the UORC database (Figure 20). Wetland Database for UORC - 89 -
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COALTECH UPPER OLIFANTS RIVER CATCH
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The following aspects are included
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The most common wetland types in th
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The attributes allocated based on t
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6. DATABASE CONSTRAINTS............
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Addendums Addendum A - Plant specie
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Figure 1. Extent of the UORC (refer
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The aim of the wetland layer is to
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3.3 Wetland biodiversity Wetlands p
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Table 1: Species of concern Species
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Species name Common name Hottentot
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Species name Common name Cordylus g
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3.3.2 Birds Various bird species ut
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3.3.6 Fish The UORC has a low diver
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Figure 2. Schematic illustration of
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3.4.1.2 Floodplain riparian Floodpl
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3.4.4 Other non-riparian wetlands O
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3.5.1.2 Groundwater recharge Variou
Page 37 and 38: More important in the removal of me
Page 39 and 40: The flow velocity in the channel of
Page 41 and 42: The most important fishing activity
Page 43 and 44: 3.5.6.3 Livestock Diseases Various
Page 45 and 46: 3.6.2 Mining and Quarrying There is
Page 47 and 48: • Dwars-in-die-wegspruit at the l
Page 49 and 50: 3.6.4 Burning Wetlands are burnt on
Page 51 and 52: 3.6.9 Alien Fauna and Flora 3.6.9.1
Page 53 and 54: Category 3 plant invaders are plant
Page 55 and 56: o The Fish Assemblage Integrity Ind
Page 57 and 58: Figure 4. The ecoregions of the Oli
Page 59 and 60: Sixteen fish species (four of which
Page 61 and 62: Figure 5. Extent of the UORC accord
Page 63 and 64: 3.9 Common wetland types in UORC Ac
Page 65 and 66: In a wetland assessment conducted a
Page 67 and 68: In a wetland study at Douglas Colli
Page 69 and 70: Figure 8. Status of assessed wetlan
Page 71 and 72: Figure 9. Portion of the wetland la
Page 73 and 74: Figure 11. Portion of the water bod
Page 75 and 76: Figure 13. Portion of the separated
Page 77 and 78: Figure 15. Portion of the wetland l
Page 79 and 80: Since the field verification site v
Page 81 and 82: Figure 18. Portion of the final wet
Page 83 and 84: Upon a request from DWAF the status
Page 85 and 86: 5.8 Functions The functions likely
Page 87: 5.11 Wetland types The entire catch
Page 91 and 92: Figure 21. The wetland in the UORC
Page 93 and 94: 8.2 Mapping o Small wetlands (of le
Page 95 and 96: The attributes in the attribute tab
Page 97 and 98: 10. REFERENCES Abbott Grobicki (Pty
Page 99 and 100: Goudie, A.S. & Thomas, D.S.G. 1985.
Page 101 and 102: Merot, P., Squividant, H., Aurousse
Page 103 and 104: Wilson, R.T. 2003. Animal health an
Page 105 and 106: Addendum A - Plan species list Wetl
Page 107 and 108: var. lachnantha Lamiaceae Ajuga oph
Page 109 and 110: Asteraceae Berkheya onopordifolia B
Page 111 and 112: Poaceae Chloris pycnothrix Chloroph
Page 113 and 114: Poaceae Boraginaceae incompletus Cy
Page 115 and 116: Poaceae Echinochloa cruspavonis * *
Page 117 and 118: Asteraceae Gamochaeta subfalcata Y
Page 119 and 120: Sterculiaceae Sterculiaceae Poaceae
Page 121 and 122: Cyperaceae Kyllinga erecta Kyllinga
Page 123 and 124: Asteraceae Nidorella anamola Nympho
Page 125 and 126: Polygonaceae Apiaceae Poaceae Apiac
Page 127 and 128: Brassicaceae Rorippa nudiuscula * *
Page 129 and 130: Poaceae Setaria verticillata * Malv
Page 131 and 132: Asteraceae Ursinia nana * * * Lenti
Page 133 and 134: Addendum B - Mammal species list We
Page 135 and 136: Cynictis Yellow Carnivora penicilla
Page 137 and 138: Addendum C - Bird species list Wetl
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Actitis hypoleucos Actophilornis Co
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Ceryle rudis Nectarinia Pied Kingfi
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Eremopterix verticalis Estrilda ast
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Netta erythrophthalma Numida meleag
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Spizocorys conirostris Pinkbilled L
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Addendum D - Reptile species list W
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Elapidae Naja haje Egyptian cobra X
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Group Species name Common name Pipi
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Addendum F - Fish species list Wetl
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Austroglansis sclateri X X Barbus a
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Phylum Group Species name Common na
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Arachnida Tanycypris obtusa Hydroze
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gibba Daphnia pulex Simocephalus ca
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Ischnura senegalensis Pseuddgrion s
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Micronecta sp. Micronecta piccanin
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Hydraenidae Hydrophilida e Berosus
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MOLLUSCA Simulium adersi Simulium ?
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